Axisymmetric dynamo action is possible with anisotropic conductivity

Abstract

A milestone of dynamo theory is Cowling's theorem, known in its modern form as the impossibility for an axisymmetric velocity field to generate an axisymmetric magnetic field by dynamo action. Using an anisotropic electrical conductivity we show that an axisymmetric dynamo is in fact possible with a motion as simple as solid body rotation. On top of that the instability analysis can be conducted entirely analytically, leading to an explicit expression of the dynamo threshold which is the only example in dynamo theory.

4 pages, 4 figures

References in corpus (1)

• Dynamo action in sliding plates of anisotropic electrical conductivity

Cited by in corpus (4)

• Dynamo action in sliding plates of anisotropic electrical conductivity
• Axisymmetric dynamo action produced by differential rotation, with anisotropic electrical conductivity and anisotropic magnetic permeability
• Enhanced dynamo growth in nonhomogeneous conducting fluids
• Fast and Furious dynamo action in the anisotropic dynamo